Add error reporting (via errno) to getauxval().

[BZ 15846] As discussed in the recent thread on my $EXEC_ORIGIN patch
and in BZ 15846, getauxval() presently has no unambiguous way of
reporting an error condition.  It currently returns zero on error, but
this may also be a valid result for some auxv entries.  As there is no
clear invalid result for all current and future auxv entries, this patch
sets errno (following a suggestion in the BZ entry).

This version of the patch also adds documentation and tests for the
value-not-found conditions in getauxval().

1 files changed, 11 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index 76e323f..173c280 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2013-12-18  Brooks Moses  <bmoses@google.com>
+
+	[BZ #15846]
+	* misc/getauxval.c: Include errno.h.
+	(__getauxval): Set errno to ENOENT if the requested type is not
+	found.
+	* misc/sys/auxv.h (getauxval): Document that it may set errno;
+	don't declare with __attribute_const__.
+	* elf/tst-auxv.c: Add tests for errno and type-not-found case.
+	* manual/startup.texi: Document that getauxval sets errno.
+
 2013-12-18  Joseph Myers  <joseph@codesourcery.com>
 
 	* math/auto-libm-test-in: Add tests of jn and yn.